Influence of the height distribution of microscopic surface roughness on photometric estimates of the standard deviation from the surface profile

1995 ◽  
Vol 38 (8) ◽  
pp. 880-883
Author(s):  
V. V. Syt'ko ◽  
D. V. Dem'yanenko ◽  
Yu. N. Sviridenko ◽  
N. I. Aleshkevich ◽  
V. F. Sholokh
Keyword(s):  
Surface Roughness ◽  
Standard Deviation ◽  
Surface Profile ◽  
Height Distribution ◽  
Microscopic Surface

Surface Topography Changes in Polymer-Metal Sliding—II

1983 ◽  
Vol 105 (4) ◽  
pp. 526-531 ◽  
Author(s):  
V. K. Jain ◽  
S. Bahadur
Keyword(s):  
Surface Roughness ◽  
Standard Deviation ◽  
High Density Polyethylene ◽  
Surface Profile ◽  
Data Acquisition System ◽  
Radius Of Curvature ◽  
Roughness Parameters ◽  
Poly Vinyl Chloride ◽  
Polymer Metal

The variation in the surface topographical parameters for the case of sliding between high density polyethylene and poly(vinyl chloride) pin ends and a steel disk periphery was investigated. Sliding surface profile ordinate data were obtained at 2μm intervals using a data acquisition system, both along and perpendicular to the direction of sliding. A number of surface roughness parameters, viz., the r.m.s. and c.l.a. roughness, the slope, density, and radius of curvature of asperities, the standard deviation and distribution of profile ordinates, slopes, radii of curvatures and heights of asperities were calculated using a Fortran IV computer program. The analysis showed that the surface parameters undergo a marked variation during the early part of sliding, but the variation is statistically insignificant during the later part. It was found that the standard deviation of peak heights can be approximated by the r.m.s. surface roughness.

Analysis of contact and bending stiffness for Curvic couplings considering contact angle and surface roughness

2019 ◽  
Vol 233 (6) ◽  
pp. 1257-1267 ◽  
Author(s):  
Younghun Yu ◽  
Bora Lee ◽  
Yongjoo Cho
Keyword(s):  
Surface Roughness ◽  
Contact Angle ◽  
Standard Deviation ◽  
Bending Stiffness ◽  
Height Distribution ◽  
Average Radius ◽  
Asperity Height ◽  
Surface Parameter ◽  
Tangential Stiffness ◽  
Nominal Contact Area

This paper develops a method for calculating the contact and bending stiffness of a Curvic coupling, and investigates stiffness changes according to the coupling shape and surface roughness characteristics. The surface of the on-site Curvic coupling is chosen as reference for a most accurate simulation. The three parameters representing the surface roughness characteristics—the standard deviation of the asperity height distribution, the average radius of asperities, and the density of asperity on the nominal contact area—are calculated with a profile of the coupling surface through a random process: the contact problem between rough surfaces is tackled using the Greenwood-Williamson model, the Curvic coupling is modeled assuming that it has as many teeth as possible within the machining limits depending on the contact angle, and the tangential stiffness resulting from the contact angle is calculated by dividing into the stick and slip regions, and is taken into account in terms of total stiffness. With this, results showed that using Curvic couplings reduces stiffness than using flat disc couplings because of the contact angle, and that the standard deviation of rough surface height is the most crucial surface parameter affecting stiffness.

Paper 6: Assessment of Face Seal Performance Based on the Parameters of a Statistical Representation of Surface Roughness

1967 ◽  
Vol 182 (11) ◽  
pp. 101-107 ◽  
Author(s):  
L. A. Mitchell ◽  
M. D. Rowe
Keyword(s):  
Surface Roughness ◽  
Standard Deviation ◽  
Surface Profile ◽  
Real Surface ◽  
Face Seal ◽  
Statistical Representation ◽  
Adequate Information ◽  
Centre Line ◽  
Sealing Performance ◽  
The Mean

Most methods commonly used to describe real surface roughness do not provide adequate information to enable predictions to be made of fluid leakage between two surfaces. To carry out such an analysis it is essential to know the depths of the remaining valleys at all stages of compression. It is shown that, when the distributions of peak and valley levels are defined, load-compression and load-leakage relationships can be derived if wedge-shaped asperities of constant apex semi-angle are assumed. The results suggest that a convenient quantity for specifying the form of a surface profile is the ratio of the distance between the mean peak and mean valley levels to the standard deviation of the distributions ( d/σ). For the best sealing performance d/σ should be as large as possible, whilst the centre-line average (c.l.a.), which provides a measure of the scale of the roughness, should be as small as possible.

A method for describing biofilm surface roughness using geostatistical techniques

1995 ◽  
Vol 32 (8) ◽  
pp. 91-98 ◽  
Author(s):  
J. T. Gibbs ◽  
P. L. Bishop
Keyword(s):  
Surface Roughness ◽  
Standard Deviation ◽  
Correlation Coefficient ◽  
Surface Profile ◽  
Fundamental Property ◽  
Surface Characteristics ◽  
Data Set ◽  
Trickling Filters ◽  
Geostatistical Techniques ◽  
Rotating Biological Contactors

Biofilm reactors, such as rotating biological contactors (RBCs) and trickling filters, have been used to treat both municipal and industrial waste streams. One fundamental property of biofilms which may affect their performance is surface roughness, or the magnitude of variability in height over the structure's profile. This property has an effect on the rate of diffusion of nutrients into the biofilm for degradation through its influence on the thickness of the concentration boundary layer. The method presented here to quantify the surface characteristics of a biofilm involves the in situ analysis of biofilm surface profile data collected at discrete points. For each point, a microprobe is lowered from some datum above the surface, and the distance down to the biofilm surface is measured at that point. Statistical analysis performed on the data set produces the correlation coefficient between heights on the biofilm surface at various separation intervals. A graph relating the correlation coefficient to the separation interval between heights is constructed from many points to determine the length over which points with low correlation can be collected. A set of nearly independent height data collected at that length interval is then analyzed for mean and standard deviation. The resulting statistics are characteristic of the magnitude of the variability between independent heights on the surface profile, and can be used to compare and contrast the roughness of biofilm surfaces. This method was used to define the roughness of artificial and real biofilm surfaces. Artificial biofilms, which were made from agar roughed with sand paper of varying grit size, were found to have distinct and consistent roughness, as determined by this method. It was useful to compare the standard deviation (roughness) of real biofilms to these values, because the roughness of sand paper is easily observable, and standardized.

Optimal parameters of abrasive flow finishing for hip joint implants

2021 ◽  
pp. 095440542199561
Author(s):  
Yahya Choopani ◽  
Mohsen Khajehzadeh ◽  
Mohammad Reza Razfar
Keyword(s):  
Surface Roughness ◽  
Standard Deviation ◽  
Femoral Head ◽  
Hip Joint ◽  
Spherical Shape ◽  
Shape Deviation ◽  
Head Surface ◽  
Joint Implants ◽  
Finishing Processes ◽  
Abrasive Flow Finishing

Total hip arthroplasty (THA) is one of the most well-known orthopedic surgeries in the world which involves the substitution of the natural hip joint by prostheses. In this process, the surface roughness of the femoral head plays a pivotal role in the performance of hip joint implants. In this regard, the nano-finishing of the femoral head of the hip joint implants to achieve a uniform surface roughness with the lowest standard deviation is a major challenge in the conventional and advanced finishing processes. In the present study, the inverse replica fixture technique was used for automatic finishing in the abrasive flow finishing (AFF) process. For this aim, an experimental setup of the AFF process was designed and fabricated. After the tests, experimental data were modeled and optimized to achieve the minimum surface roughness in the ASTM F138 (SS 316L) femoral head of the hip joint through the use of response surface methodology (RSM). The results confirmed uniform surface roughness up to the range of 0.0203 µm with a minimum standard deviation of 0.00224 for the femoral head. Moreover, the spherical shape deviation of the femoral head was achieved in the range of 7 µm. The RSM results showed a 99.71% improvement in the femoral head surface roughness (0.0007) µm under the optimized condition involving the extrusion pressure of 9.10 MPa, the number of finishing cycles of 95, and SiC abrasive mesh number of 1000.

scholarly journals Influence of Relative Displacement on Surface Roughness in Longitudinal Turning of X37CrMoV5-1 Steel

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1317
Author(s):  
Michal Skrzyniarz ◽  
Lukasz Nowakowski ◽  
Edward Miko ◽  
Krzysztof Borkowski
Keyword(s):  
Surface Roughness ◽  
Standard Deviation ◽  
Surface Texture ◽  
Roughness Parameter ◽  
Relative Displacement ◽  
Edge Radius ◽  
Shaping Process ◽  
Feed Value ◽  
Longitudinal Turning ◽  
Final Effect

The shaping process of surface texture is complicated and depends on many factors and phenomena accompanying them. This article presents the author’s test stand for the measurement of relative displacements in a tool–workpiece system during longitudinal turning. The aim of this study was to determine the influence of edge radius on the relative displacement between the tool and workpiece. The cutting process was carried out with inserts with different edge radii for X37CrMoV5-1 steel. As a result of the research, vibration charts of the tool–workpiece system were obtained. In the range of feed 0.03–0.18 mm/rev, the values of the standard deviation of relative displacements in the x-axis were obtained in the range of 0.36–0.78 μm for the insert with an edge radius of rn = 48.8 μm. As a result of the work, it was determined that for the feed value of 0.12 mm/rev for all inserts, the relative displacements are the smallest. As the final effect, the formula for forecasting the Ra roughness parameter was presented.

Hydrodynamic Lubrication and Wear in Wavy Contacting Face Seals

1978 ◽  
Vol 100 (1) ◽  
pp. 81-90 ◽  
Author(s):  
A. O. Lebeck ◽  
J. L. Teale ◽  
R. E. Pierce
Keyword(s):  
Surface Roughness ◽  
Hydrodynamic Lubrication ◽  
Surface Profile ◽  
Operating Conditions ◽  
Face Seal ◽  
Hydrodynamic Load ◽  
Surface Waviness ◽  
Wear Rates ◽  
Elastic Deflection ◽  
Face Seals

A model of face seal lubrication is proposed and developed. Hydrodynamic lubrication for rough surfaces, surface waviness, asperity load support, elastic deflection, and wear are considered in the model. Predictions of the ratio of hydrodynamic load support to asperity load support are made for a face seal sealing a low viscosity liquid where some contact does occur and surface roughness is important. The hydrodynamic lubrication is caused by circumferential surface waviness on the seal faces. Waviness is caused by initial out of flatness or any of the various distortions that occur on seal ring faces in operation. The equilibrium solution to the problem yields one dimensional hydrodynamic and asperity pressure distributions, mean film thickness, elastic deflection, and friction for a given load on the seal faces. The solution is found numerically. It is shown that the fraction of hydrodynamic load support depends on many parameters including the waviness amplitude, number of waves around the seal, face width, ring stiffness, and most importantly, surface roughness. For the particular seal examined the fraction of load support would be small for the amount of waviness expected in this seal. However, if the surface roughness were lower, almost complete lift-off is possible. The results of the analysis show why the initial friction and wear rates in mechanical face seals may vary widely; the fraction of hydrodynamic load support depends on the roughness and waviness which are not necessarily controlled. Finally, it is shown how such initial waviness effects disappear as the surface profile is altered by wear. This may take a long or short time, depending on the initial amount of hydrodynamic load support, but unless complete liftoff is achieved under all operating conditions, the effects of initial waviness will vanish in time for steady state conditions. Practical implications are drawn for selecting some seal parameters to enhance initial hydrodynamic load support without causing significant leakage.

Effect of Workpiece Hardness on Surface Microgeometry when Hard Turning with Ceramic Inserts

2013 ◽  
Vol 581 ◽  
pp. 176-181 ◽  
Author(s):  
Ildikó Maňková ◽  
Jozef Beňo ◽  
Marek Vrabel'
Keyword(s):  
Surface Roughness ◽  
Hard Turning ◽  
Surface Profile ◽  
Surface Finishing ◽  
Oxide Ceramic ◽  
Part Surface ◽  
Cutting Force Components ◽  
Finish Hard Turning ◽  
Force Components ◽  
Mixed Ceramic

Hard turning provides an alternative to grinding in some finishing operations. This paper deals with analysis of part surface finishing when turning hardened steel heat-treated on hardness of 46, 55 and 60 HRC with mixed oxide ceramic inserts. Average surface roughness Ra has been widely used in industry it is known that the single parameter Ra is inadequate to define the functionality of a surface. Two different surfaces with similar values of Ra can behave differently under loading conditions. The surface profile 2D and 3D parameters are assessed. The influence of workpiece hardness on surface roughness parameters and cutting force components is investigated. Results show that finish hard turning with mixed ceramic tool produces surface profile comparable to those produced by grinding.

scholarly journals Effects of Microstructure, Mechanical and Physical Properties on Machinability of Graphite Cast Irons

Metals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 285 ◽  
Author(s):  
Jiangzhuo Ren ◽  
Fengzhang Ren ◽  
Fengjun Li ◽  
Linkai Cui ◽  
Yi Xiong ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Surface Roughness ◽  
Standard Deviation ◽  
Cutting Force ◽  
Volume Fraction ◽  
Internal Surface ◽  
Drilling Process ◽  
Turning Process ◽  
Cast Irons ◽  
Mechanical And Physical Properties

Flake (FGI) and spheroidal (SGI) graphite cast irons are often used to produce workpieces, which often need to be machined. Machinability differences under various machining methods are the basis for choosing machining equipment and technology. In this work, FGI and SGI were used to produce tractor front brackets, and the machinability of both materials under turning and drilling processes was compared. The machinability (turning and drilling ability) has been evaluated in terms of machining load, chips shape, surface roughness, and tool temperature. The influence of materials microstructure and thermal conductivity on the machinability was analyzed. In the turning process, the cutting force and its standard deviation of the FGI were larger than the SGI due to the higher volume fraction of pearlite. The surface roughness was similar in both materials. In the drilling process, the even action of the friction and cutting force on the bit turned into similar drilling loads for both materials. Higher friction and lower thermal conductivity caused a higher bit temperature in SGI drilling compared to FGI. The chip breaking was worse in SGI drilling, where the longer chips scratched the internal surface of the holes, resulting in the higher surface roughness.

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